The  contains:

• Array-Routines
• Compute the size of an array
• The best way for string arrays
• Debug-Routines

Array-Routines

Compute the size of an array

int int_array [] = { 5, 10, 13, 24};

int array_size = sizeof(int_array)/sizeof(int_array[0]);
int max_nr_in_array = array_size-1;

• arrayname is a pointer to the first element of the array
• arrayindex starts with 0
• arrayindex ends with size-1

But:
If you give the array as an argument to a function, inside the function you can´t compute the arraysize!

Example:
Here you can look for an example programme or the same as html-output.

You can download the example (incl. html-output) and compile it with:

cc -Wall -O2 -o array1 array1.c

./array1

The sizeof(int) is: 4
The sizeof(array) is: 12
The sizeof(array[0]) is: 4
The sizeof(*array) is: 4

The address of array is: 0xbffff87c
The address of &array[0] is: 0xbffff87c
The address of &array[1] is: 0xbffff880
The address of array+1 is: 0xbffff880

The value of *array is: 1
The value of array[0] is: 1
The value of *array+1 is: 2
The value of array[1] is: 2

The number of elements in array is: 3
The number of elements in array is: 3

The address of array in prtfunc is: 0xbffff87c
The sizeof(array) in prtfunc is: 4
The sizeof(&array) in prtfunc is: 4

array[0] = 1 and has address: 0xbffff87c
array[1] = 2 and has address: 0xbffff880
array[2] = 3 and has address: 0xbffff884

The following thinks only work with a pointer to our array -
because array is a const pointer to first element and
can´t change [get an compiler error]!
Get this pointer with:
        int *a_p = array;

To increment the second element do:
         ++(*(++a_p))
New values are:
array[0] = 1 and has address: 0xbffff87c
array[1] = 3 and has address: 0xbffff880
array[2] = 3 and has address: 0xbffff884

To increment the first element do:
         ++(*a_p)
New values are:
array[0] = 2 and has address: 0xbffff87c
array[1] = 3 and has address: 0xbffff880
array[2] = 3 and has address: 0xbffff884

The best way for string arrays

const char *days[] = { "Monday", "Tuesday",
                       "Wednesday", "Thursday",
                       "Friday", "Saturday", "Sunday"};

Advantage of this way:
If you append or insert or delete an element you don´t must change your source!
 

Debug-Helper